The present application claims priority under 35 U.S.C. code 119 to Korean Application No. 2000-53074 filed on Sep. 7, 2000, which is hereby incorporated by reference in its entirety for all purposes.
1. Field of the Invention
The present invention relates to a method of cleaning a polishing pad conditioner and an apparatus for performing the same, more particularly, to a method of cleaning a polishing pad conditioner of a semiconductor device and an apparatus for performing the same, by which particles sticking to a diamond disc of the polishing pad conditioner can be effectively removed.
2. Description of the Related Art
Generally, a semiconductor chip is fabricated by treating a wafer made of silicon by using a semiconductor manufacturing device. The wafer is fabricated into a semiconductor chip through semiconductor manufacturing processes such as lithography, chemical and mechanical polishing, chemical or physical deposition and plasma etching processes.
While the semiconductor manufacturing processes are being carried out, particles such as compounds or dusts remain on a surface of the wafer. In addition, the particles stick to the semiconductor manufacturing device, thereby resulting in processing failure. Accordingly, a cleaning process for removing the particles is carried out while the wafer is being fabricated. Various kinds of cleaning methods and devices have been suggested. For example, a cleaning device having a brush for cleaning a spin chuck which coats a photo resist on the wafer is disclosed in Japanese Laid-open Publication No. 10-294261. The cleaning device exhausts nitrogen gas while injecting a cleaning liquid such as acetone so as to remove the particles.
The cleaning process has to be continuously carried out while the semiconductor manufacturing process is being performed. Particularly, the cleaning process is inevitably required after the chemical and mechanical polishing process is finished. Since the chemical and mechanical polishing process polishes the wafer by introducing slurries on to the surface of the wafer, a great amount of slurries stick to the wafer and the chemical and mechanical polishing device. The slurries remaining on the wafer or the chemical and mechanical polishing device are solidified, thereby forming particles which scratch the wafer.
The chemical and mechanical polishing device includes a platen on which a polishing pad is installed, a polishing head for sucking and pressing the wafer, and a polishing pad conditioner for conditioning the polishing pad so as to prevent abrasion of the polishing pad. The slurries also stick to the parts of the chemical and mechanical polishing device while the polishing process is being carried out, so the cleaning process has to be performed with respect to the parts of the chemical and mechanical polishing device after the polishing process has been finished. In addition, the slurries can flow into a driving part for driving the parts of the chemical and mechanical polishing device, thereby resulting in faulty operation of the driving part. U.S. Pat. No. 6,033,290 discloses a polishing pad conditioner using a fluid fuzzy system for preventing impurities including slurries from flowing into an interior of a conditioner head which drives a polishing pad conditioner in the upward and downward directions.
The conditioning of the polishing pad is carried out by using a diamond disc attached to the polishing pad conditioner. The diamond disc applies a predetermined pressure to an upper surface of the polishing pad so as to improve the quality of the upper surface of the polishing pad. However, since the diamond disc directly makes contact with the slurries formed on the polishing pad, the slurries can stick to the diamonds on the diamond disc. As time goes by, the slurries sticking to the diamonds are solidified so that the conditioning effect of the diamond disc on the polishing pad is lowered by the solidified slurries. In addition, the solidified slurries can drop onto the surface of the polishing pad while the polishing work is being carried out, so that the upper surface of the wafer can be scratched. Accordingly, cleaning of the polishing pad conditioner after the polishing process is necessarily required. The cleaning of the polishing pad conditioner is performed by using a polishing pad cleaning apparatus installed at one side of a polishing device.
FIG. 1 shows a conventional polishing pad conditioner cleaning device. Particularly, the polishing pad conditioner cleaning apparatus shown in FIG. 1 cleans a diamond disc for conditioning a polishing pad, in a polishing pad conditioner. Referring to FIG. 1, the polishing pad conditioner cleaning apparatus has a cleaning bath 10 which contains a cleaning liquid 12 for cleaning the polishing pad conditioner. The polishing pad conditioner coupled with a diamond disc is immersed into the cleaning liquid 12 in the cleaning bath 10, after the cleaning work of the polishing pad is completed. The cleaning liquid includes deionized water. An upper portion of the cleaning bath 10 is opened. A cleaning liquid supplying part 14 for supplying the cleaning liquid into the cleaning bath 10 is provided at a side of the cleaning bath 10. A brush 16 is provided at a lower portion of an inner portion of the cleaning bath 10. After the polishing pad conditioner coupled with the diamond disc is immersed into the cleaning bath 10, the brush 16 makes contact with the diamond disc so as to remove particles including the slurries, from the diamond disc. A draining part 18 is provided at an outer portion of the cleaning bath 10. The draining part 18 collects overflow cleaning liquid 12 from the cleaning bath 10, and drains the overflow cleaning liquid to an exterior.
The polishing pad conditioner cleaning apparatus having the above structure cleans the polishing pad conditioner as follows. When the polishing process for flattening the surface of the wafer has been finished, the polishing pad conditioner is conveyed into the polishing pad cleaning apparatus. Then, the polishing pad conditioner is immersed into the cleaning liquid 12 in the cleaning bath 10. The diamond disc of the polishing pad conditioner makes contact with the brush 16 installed at the lower portion of the inner portion of the cleaning bath 10, so that the slurries sticking to the diamond disc are removed. The cleaning liquid 12 is supplied from the cleaning liquid supplying part. The cleaning liquid 12 overflows from the cleaning bath 10, as the cleaning liquid 12 is continuously supplied into the cleaning bath 10.
However, the slurries sticking to the polishing pad conditioner cannot be completely removed by simply contacting the polishing pad conditioner with the brush. The slurries thus remaining in the polishing pad conditioner are solidified so that the conditioning effect of the polishing pad conditioner on the polishing pad is lowered, which may result in the surface of the wafer becoming scratched. In addition, the slurries removed from the polishing pad conditioner settle at the bottom of the cleaning bath without flowing out of the cleaning bath, so that the slurries become deposited in the brush while the cleaning process is being carried out. The slurries deposited in the brush can contaminate the diamond disc of the polishing pad conditioner, so that it also becomes necessary to periodically remove the slurries from the brush. However, removing the slurries from the brush is very difficult and requires a lot of time. In addition, since the diamond disc frequently makes contact with the brush while the cleaning process is being carried out, parts of the brush can be separated from the brush. The separated parts of the brush can stick to the diamond disc. In this case, the surface of the wafer is scratched by the separated parts of the brush sticking to the diamond disc during conditioning of the polishing pad using the diamond disc.
The present invention is therefore directed to a method of cleaning a polishing pad conditioner, and an apparatus for performing the same, which substantially overcomes one or more of the problems due to the limitations and disadvantages of the related art.
The present invention has been made to solve the problems of the related art, and accordingly, a first object of the present invention is to provide a method of cleaning a polishing pad conditioner, which can effectively remove particles sticking to the polishing pad conditioner.
A second object of the present invention is to provide a cleaning apparatus for performing the cleaning method.
To accomplish the first object of the present invention, there is provided a method of cleaning a polishing pad conditioner including immersing the polishing pad conditioner into a cleaning bath containing a cleaning liquid. The cleaning liquid is bubbled by injecting an inert gas into the cleaning liquid from a bottom of the cleaning bath. Additional cleaning liquid is supplied into the cleaning bath.
To accomplish the second object of the present invention, there is provided an apparatus for cleaning a polishing pad conditioner, including a cleaning bath containing a cleaning liquid. A gas injecting part injects an inert gas into the cleaning liquid from a bottom of the cleaning bath. A cleaning liquid supplying part supplies the cleaning liquid into the cleaning bath. The polishing pad conditioner coupled with a diamond disc is immersed into the cleaning liquid and the inert gas is injected into the cleaning liquid from the bottom of the cleaning bath thereby bubbling the cleaning liquid. By the bubbling of the cleaning liquid, the particles including slurries sticking to the polishing pad conditioner are effectively removed. In addition, the particles removed from the polishing pad conditioner overflow from the cleaning bath by the pressure of the inert gas injected from the bottom of the cleaning bath, without floating on the cleaning liquid or settling at the bottom of the cleaning bath. Accordingly, the polishing pad conditioner is prevented from being contaminated by the particles in the cleaning bath.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.